[Oblique puncture approach via anterolateral to C2: a study of imaging anatomy on corpses]

Objective: To determine the anatomical relation between the carotid artery or laryngopharynx and the needle path via anterolateral oblique approach to C2 vertebral body, and whether the simulated path can direct the actual procedure. Methods: Contrast agent was injected into bilateral carotid arteries of 10 fresh cadavers (20 sides), and then CT scans were performed on each subject. Bilateral simulated puncture paths were simulated on the image of two-dimensional reconstruction CT. The distance between the puncture site and middle line(AC), the angle between the simulated puncture paths and the median sagittal plane (AOB), the distance between the simulated puncture paths and the side wall of hypopharynx, or the carotid artery was measured respectively. Under the guidance of fluoroscopy, oblique puncture via anterolateral to C2 was performed according to the simulated parameters, and then CT was done. The actual needle path was measured on the image of two-dimensional reconstruction CT. The outcomes were compared by using paired t test between groups. Results: Bilateral simulated puncture paths in all 10 cadavers were achieved on the image of CT. The bilateral punctures via anterolateral to C2 were successfully performed under fluoroscopic guidance in 10 cadavers, and the actual needle path could be showed on the image of two-dimensional reconstruction CT. The AC, angle AOB, the distance to carotid artery and side wall of laryngopharyngeal of the left simulated path was(4.7±1.0)cm, (33±8)°, (6.7±2.6)mm, (6.6±2.8)mm, respectively; and those in the right side was(5.2±1.3) cm, (36±8)°, (7.5±2.2) mm, (7.2±2.5) mm, respectively.The AC, angle AOB, the distance to carotid artery and side wall of laryngopharyngeal of the left actual needle was(4.5±1.1) cm, (33±9) °, (6.7±3.0) mm, (7.1±3.9) mm, respectively; and those in the right side was(5.1±1.5) cm, (35±10) °, (7.4±2.1) mm, (7.2±2.6) mm, respectively.And the actual and simulation data of both sides were compared and no significant differences was found by t test (t=0.104-1.882, all P>0.05). Conclusion: The simulated approach via anterolateral to C2 can be achieved on the image of two-dimensional reconstruction CT, it is consistent with the real needle path and can be used to direct the actual practice to improve the accuracy and safety.